Lower hypoxic ventilatory response in smokers compared to non-smokers during abstinence from cigarettes.

BACKGROUND: Carotid body O2-chemosensitivity determines the hypoxic ventilatory response (HVR) as part of crucial regulatory reflex within oxygen homeostasis. Nicotine has been suggested to attenuate HVR in neonates of smoking mothers. However, whether smoking affects HVR in adulthood has remained unclear and probably blurred by acute ventilatory stimulation through cigarette smoke. We hypothesized that HVR is substantially reduced in smokers when studied after an overnight abstinence from cigarettes i.e. after nicotine elimination. METHODS: We therefore determined the isocapnic HVR of 23 healthy male smokers (age 33.9 ± 2.0 years, BMI 24.2 ± 0.5 kg m-2, mean ± SEM) with a smoking history of >8 years after 12 h of abstinence and compared it to that of 23 healthy male non-smokers matched for age and BMI. RESULTS: Smokers and non-smokers were comparable with regard to factors known to affect isocapnic HVR such as plasma levels of glucose and thiols as well as intracellular levels of glutathione in blood mononuclear cells. As a new finding, abstinent smokers had a significantly lower isocapnic HVR (0.024 ± 0.002 vs. 0.037 ± 0.003 l min-1 %-1BMI-1, P = 0.002) compared to non-smokers. However, upon re-exposure to cigarettes the smokers' HVR increased immediately to the non-smokers' level. CONCLUSIONS: This is the first report of a substantial HVR reduction in abstinent adult smokers which appears to be masked by daily smoking routine and may therefore have been previously overlooked. A low HVR may be suggested as a novel link between smoking and aggravated hypoxemia during sleep especially in relevant clinical conditions such as COPD.

Adherence to oral anticoagulation in secondary stroke prevention--the first year of direct oral anticoagulants.

BACKGROUND: Patients with ischemic stroke caused by atrial fibrillation (AF) have a high risk of recurrence without adequate secondary prevention with oral anticoagulation (OAC). We investigated adherence to OAC in the first year after introduction of direct oral anticoagulants. METHODS: In 284 appropriate patients, the rate of anticoagulation (AC) at discharge, adherence at 90 days and 1 year, changes between substances, and predictors for adherence to AC were analyzed. Functional outcome was assessed using the modified Rankin Scale score. RESULTS: AC was initiated in 70.3% of survivors before discharge. In these patients, only 8.6% and 9.9% discontinued AC after 90 days and 1 year, respectively. In 22.1%, AC was recommended but not started before discharge. Only 53.2% of them received AC at 90 days, increasing to 67.5% at 1 year. A total of 7.6% of patients were deemed unsuitable for AC, none of them subsequently received AC. Overall, 85.4% of patients suitable for AC were treated at 1-year follow-up. No independent predictors for withholding AC were identified. Switching of medication occurred in only a minority of patients within the first year. CONCLUSIONS: AC is feasible in more than 90% patients with acute ischemic stroke and AF. When initiated during the acute hospital stay, AC is discontinued in only a minority of patients. However, if AC is recommended but not started during initial hospitalization the rate of AC treatment at 90 days and 1 year is much lower. Therefore, AC should be initiated within the acute hospital stay whenever possible.

Impaired renal function in stroke patients with atrial fibrillation.

BACKGROUND: Stroke patients with atrial fibrillation (AF) are prone to have comorbidities such as impaired renal function. Because poly-pharmacotherapy is often required in those patients, renal function is important to consider in light of renally cleared medications such as direct oral anticoagulants. In this study, we analyzed frequency and predictors for impaired renal function and its impact on functional outcome in stroke patients with underlying AF. METHODS: We analyzed 272 patients with acute ischemic stroke and AF of our prospective, observational stroke database. Estimated glomerular filtration rate (eGFR) was calculated on admission and during hospitalization from the equation of the Modification Diet for Renal Disease. Outcome measures included mortality and functional outcome at 90 days, assessed as modified Rankin Scale (mRS) score. RESULTS: On admission, impaired renal function was found in 41.5% (n = 113) and was associated with worse 90-day outcome (mRS score ≤ 2: 26.5% versus 45.9%, P = .001) and a higher mortality rate (23.9% versus 14.5%, P = .043). Multivariate logistic regression identified older age and history of myocardial infarction as independent predictors of renal dysfunction on admission (P < .05). Normalization of eGFR during hospitalization was achieved in 55.8%. CONCLUSIONS: In patients with acute ischemic stroke and AF, impaired renal function on admission is frequent and associated with worse outcome. Normalization of eGFR can often be achieved during hospitalization, but in everyday life, fluctuations of renal function because of infection or dehydration have to be considered. Careful monitoring of renal status is indispensable and should influence drug treatment decisions.

Correlation of age and haematoma volume in patients with spontaneous lobar intracerebral haemorrhage.

BACKGROUND: Lobar intracerebral haemorrhage (LH) is gaining importance in the ageing population, but there are only limited data regarding specific clinical characteristics and risk factors of older patients with LH. METHODS: This retrospective analysis of patients with spontaneous supratentorial haemorrhage included 174 consecutive patients (78 LH and 96 deep ICH (DH)). Clinical data including the preadmission status, neuroradiological findings, initial presentation, treatment and outcome were evaluated using institutional databases, patients' medical charts and mailed questionnaires. Logistic regression analyses were calculated for initial parameters predisposing LH and for treatment and outcome parameters associated with LH. RESULTS: Age-stratified volume analysis revealed increasing haematoma volumes for LH (≤70 years: 26.2 ml; 70-80 years: 37 ml; >80 years: 61.3 ml), whereas DH showed no relation between volume and age (≤70 years: 10.1 ml; 70-80 years: 23.2 ml; >80 years: 12.1 ml). DH patients had significantly higher HbA1c levels. Post-ICH seizures were more frequent after LH. Logistic regression analyses identified the parameters: age, haematoma volume and post-ICH seizures to be associated with LH, whereas intraventricular haemorrhage, extraventricular drainages and elevated HbA1c were related to DH. CONCLUSION: Haematoma volumes are substantially increasing in LH patients who are older than 70 years. Pathological HbA1c levels are significantly associated and predisposing for DH. These findings further support the ongoing debate of different disease entities for supratentorial ICH (ie, association of cerebral amyloid angiopathy and lobar ICH versus diabetes induced atherosclerosis in deep ICH). Future studies should focus on identifying specific pathological characteristics and risk factors for both bleeding sites to implement specific preventive measures, that is amyloid angiopathy modulating therapies for LH, and to avoid risk factors that are specific for each haemorrhage location.

Lumbar catheter for monitoring of intracranial pressure in patients with post-hemorrhagic communicating hydrocephalus.

BACKGROUND: We investigated the feasibility and accuracy of intracranial pressure (ICP)-measurement by lumbar drainage (LD) catheter in patients with post-hemorrhagic communicating hydrocephalus (PHCH). METHODS: Patients with subarachnoid hemorrhage (SAH, n = 21) or spontaneous ganglionic hemorrhage (ICH, n = 22) with ventricular involvement and the need for external ventricular drainage (EVD) due to acute hydrocephalus were included. When EVD weaning was not feasible due to persistent hydrocephalus, an additional LD was placed, after which EVD was clamped off. During this overlap period, patients underwent simultaneous pressure recording via EVD ("EVD-ICP") and LD ("LD-ICP"). Testing included manual compression of the jugular veins and body-posture changes from supine to 30° position. After EVD removal, we evaluated sensitivity and specificity of ICP-rise >20 mmHg during continuous monitoring via LD for the detection of persistent PHCH using additional evaluation with computed tomography (CT). RESULTS: A total of 1,806 measurements were performed in 43 patients. "LD-ICP" was strongly correlated to "EVD-ICP", with determination coefficients R(2) for the baseline measurements and each of the maneuvers ranging from 0.95-0.99, and slopes ranging 0.96-1.01. Sensitivity of "LD-ICP" >20 mmHg for detection of persistent PHCH as compared to CT was 81% and specificity was 100%. Two patients with severe SAH developed reversible signs of herniation after gradually increasing differences between "LD-ICP" and "EVD-ICP" indicated a cranio-spinal pressure gradient, likely due to cerebrospinal fluid overdrainage via LD. CONCLUSION: ICP measured via LD highly and reliably correlated to ICP measured via EVD in patients with PHCH.

Repeated thrombolysis for chronologically separated ischemic strokes: a case series.

BACKGROUND AND PURPOSE: Recombinant tissue plasminogen activator is used for the treatment of acute myocardial infarction, pulmonary embolism, and acute ischemic stroke. With many years since approval of the drug and an aging population, chances increase that patients are treated twice for chronologically separated events. METHODS: We identified patients from the prospective Erlangen Stroke and Thrombolysis Database who received repeated thrombolysis for acute ischemic stroke. Baseline demographic data and clinical, laboratory, and imaging findings were analyzed. Functional outcome was assessed after 3 months. RESULTS: Eight patients treated twice and one patient with 3 treatments were identified. The median time span between first and second thrombolysis was 10 (3 to 48) months. All patients had a favorable outcome after the first treatment, and 67% of patients had a favorable outcome after the second thrombolysis. Neither allergic reactions nor other immunoreactive events were observed. CONCLUSIONS: Repeated administration of recombinant tissue plasminogen activator for chronologically separate ischemic strokes does not appear to be associated with severe immune reactions. Larger case numbers are needed to evaluate safety and efficacy of repeated systemic thrombolysis.

MRI mismatch-based intravenous thrombolysis for isolated cerebellar infarction.

BACKGROUND AND PURPOSE: Cerebellar infarctions constitute a significant proportion of ischemic strokes and carry a substantial morbidity and mortality mainly because of swelling in the posterior fossa. No specific acute therapy is established, and patients are usually excluded from intravenous thrombolysis (IVT). METHODS: Two patients presented in an extended time window of 5 and 7 hours to our emergency department with sudden onset of severe cerebellar symptoms. After emergency MRI demonstrated superior cerebellar artery (SCA) occlusion with hypoperfusion of the respective territory and only minor DWI lesions, IVT was administered. Both patients recovered within a few hours after therapy and follow-up MRI on day 1 after treatment demonstrated only minor infarction. CONCLUSIONS: We present to our knowledge the first cases of MRI mismatch-based IVT in an extended time window in patients with isolated SCA-infarctions. More studies are needed to evaluate IVT in this patient population. Modern imaging techniques might be helpful to select patients for therapy in posterior circulation strokes.

Synthesis of uracil nucleotide analogs with a modified, acyclic ribose moiety as P2Y(2) receptor antagonists.

A series of new uracil nucleotide analogs (monophosphates, triphosphates, and phosphonates) was synthesized, in which the ribose moiety was replaced by acyclic chains, including branched or linear alkyl or dialkylether linkers. 1-omega-Bromoalkyluracil derivatives (2) were converted to the corresponding alcohols by treatment with sodium hydroxide and subsequently phosphorylated using phosphorus oxychloride followed by hydrolysis to yield the monophosphates, or by coupling with diphosphate to form the triphosphates. Reaction of 2 with triethyl phosphite followed by deprotection with trimethylsilyl bromide led to the omega-phosphonylalkyluracil derivatives. These products could be further phosphorylated by converting them into their imidazolides and subsequent treatment with diphosphate yielding the corresponding UTP analogs. Nucleoside analogs with an oxygen atom in the 2'-position, which are more similar to the natural ribosides, were synthesized from silylated uracil and trimethylsilyl iodide-treated 1,3-dioxolane, or 1,3-dioxane, respectively, and subsequently phosphorylated by standard procedures. The nucleotide analogs were investigated in a functional assay at NG108-15 cells, a neuroblastomaxglioma hybrid cell line which expresses the UTP- and ATP-activated nucleotide receptor subtype P2Y(2). The acyclic nucleotide analogs were generally weaker ligands than UTP, and-in contrast to UTP-they were antagonistic. The most potent compound was diphosphoric 5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)pentylphosphonic anhydride (5c) with an IC(50) value of 92microM showing that the replacement of the alpha-phosphate by phosphonate, which leads to enhanced stability, was well tolerated.

Increased gene expression of scavenger receptors and proinflammatory markers in peripheral blood mononuclear cells of hyperlipidemic males.

Interactions between peripheral blood mononuclear cells (PBMCs) and those within plaques are suggested to be pathophysiologically relevant to lipid-induced arteriosclerosis. In this study, gene expressions of scavenger receptors (CD36, CD68), LPS receptor (CD14), proinflammatory (tumor necrosis factor alpha [TNFalpha], CD40, interleukin-1 beta [IL-1beta]) and oxidative stress-related (manganese superoxide dismutase [MnSOD]) markers were analyzed in PBMCs of clinically asymptomatic males with classical proatherogenic risk factors such as smoking and/or hyperlipidemia. PBMCs were isolated from venous blood of normolipidemic non-smokers (n = 10) and smokers (n = 8), and hyperlipidemic non-smokers (n = 9) and smokers (n = 8). RNA from PBMCs was used for PCR analyses. Plasma concentrations of oxidized low-density lipoproteins (oxLDL) were measured by ELISA. The gene expressions of CD36, CD68, CD40, TNFalpha, and MnSOD were significantly higher in PBMCs of hyperlipidemics than in normolipidemics, irrespective of whether they were smoking or not. The individual expression of these genes showed significant positive correlations with each other but also with serum cholesterol or plasma oxLDL concentrations. The higher expressions of scavenger receptors, proinflammatory and oxidative stress-related genes of PBMCs are suggested to result mainly from hyperlipidemia and the accompanied increase of oxLDL concentrations.

Good outcome of brain stem progressive multifocal leukoencephalopathy in an immunosuppressed renal transplant patient: Importance of early detection and rapid immune reconstitution.

Progressive multifocal leukoencephalopathy (PML) is a rare, opportunistic and often fatal disease of the CNS which may occur under immunosuppression in transplant patients. Brain stem PML is associated with a particularly bad prognosis. Here, we present a case of a renal transplant patient treated with mycophenolate mofetil (MMF) and tacrolimus who developed brain stem PML with limb ataxia, dysarthria and dysphagia. Diagnosis was established by typical MRI features and detection of JCV-DNA in the CSF. Immune reconstitution after stopping MMF and tacrolimus led to a complete and sustained remission of symptoms with improvement of the brain stem lesion over a follow-up over 20months. In summary, early detection of PML and consequent treatment may improve neurological outcomes even in brain stem disease with a notorious bad prognosis.

Increased cyclooxygenase-2 expression in peripheral blood mononuclear cells of smokers and hyperlipidemic subjects.

Cyclooxygenase (COX)-2 is expressed in macrophages of arteriosclerotic lesions and promotes inflammation. We investigated whether COX-2 is already expressed in peripheral blood mononuclear cells (PBMCs) of subjects possessing risk-related factors, such as in smokers and hyperlipidemics. PBMCs were isolated from the venous blood of normolipidemic nonsmokers (NL-NSM; n = 15), normolipidemic smokers (NL-SM; n = 12), hyperlipidemic nonsmokers (HL-NSM; n = 10), and hyperlipidemic smokers (HL-SM; n = 10). RNA from PBMCs was used for RT-PCR. Plasma concentrations of oxidized low-density lipoproteins (oxLDL) were measured by ELISA, those of glutamate and cystine by HPLC. The results show that COX-2 expression in PBMCs was significantly increased in the groups with cardiovascular risk factors (NL-SM, HL-SM, HL-NSM) compared with NL-NSM. COX-2 expression in PBMCs was positively correlated with concentrations of total serum cholesterol, oxLDL, glutamate, or cystine. We suggest that the elevated COX-2 expression indicates a priming of PBMCs as a response to a systemic pro-oxidative and proinflammatory shift in subjects with cardiovascular risk factors, which might also contribute to growth and instability of arteriosclerotic lesions.

Effect of thiol antioxidant on body fat and insulin reactivity.

Insulin signaling is enhanced by moderate concentrations of reactive oxygen species (ROS) and suppressed by persistent exposure to ROS. Diabetic patients show abnormally high ROS levels and a decrease in insulin reactivity which is ameliorated by antioxidants, such as N-acetylcysteine (NAC). A similar effect of NAC has not been reported for non-diabetic subjects. We now show that the insulin receptor (IR) kinase is inhibited in cell culture by physiologic concentrations of cysteine. In two double-blind trials involving a total of 140 non-diabetic subjects we found furthermore that NAC increased the HOMA-R index (derived from the fasting insulin and glucose concentrations) in smokers and obese patients, but not in nonobese non-smokers. In obese patients NAC also caused a decrease in glucose tolerance and body fat mass. Simultaneous treatment with creatine, a metabolite utilized by skeletal muscle and brain for the interconversion of ADP and ATP, reversed the NAC-mediated increase in HOMA-R index and the decrease in glucose tolerance without preventing the decrease in body fat. As the obese and hyperlipidemic patients had lower plasma thiol concentrations than the normolipidemic subjects, our results suggest that low thiol levels facilitate the development of obesity. Supplementation of thiols plus creatine may reduce body fat without compromising glucose tolerance.

Oral N-acetylcysteine reduces plasma homocysteine concentrations regardless of lipid or smoking status.

BACKGROUND: Elevated total plasma homocysteine (tHcy) is considered to be an independent cardiovascular disease risk factor, although tHcy lowering by B-vitamins improves only certain clinical endpoints. N-acetylcysteine (NAC), a thiol-containing antioxidant, acutely lowers tHcy and possibly also blood pressure. However, to our knowledge, at present no conclusive long-term evaluation exists that controls for factors such as hyperlipidemia, smoking, medication, and disease stage, all of which affect the thiol redox state, including tHcy. OBJECTIVE: We reanalyzed 2 double-blind, placebo-controlled trials in unmedicated middle-aged men, one in a hyperlipidemic group (HYL group; n = 40) and one in a normolipidemic group (NOL group; n = 42), each stratified for smokers and nonsmokers. DESIGN: We evaluated the effect of 4 wk of oral NAC (1.8 g/d) on tHcy (primary endpoint), plasma thiol (cysteine), and intracellular glutathione concentrations as well as on blood pressure. The HYL group had total cholesterol >220 mg/dL or triglycerides >150 mg/dL. RESULTS: NAC treatment significantly (P = 0.001, multivariate analysis of variance for repeated measures) lowered postabsorptive plasma concentrations of tHcy by -11.7% ± 3.0% (placebo: 4.1% ± 3.6%) while increasing those of cysteine by 28.1% ± 5.7% (placebo: 4.0% ± 3.4%) with no significant impact of hyperlipidemia or smoking. Moreover, NAC significantly decreased systolic (P = 0.003) and diastolic (P = 0.017) blood pressure within all subjects with a significant reduction in diastolic pressure in the HYL group (P = 0.008) but not in the NOL group. An explorative stepwise multiple regression analysis identified 1) post-treatment cysteine as well as 2) pretreatment tHcy and 3) albumin plasma concentrations as being significant contributors to tHcy reduction. CONCLUSIONS: Four weeks of oral NAC treatment significantly decreased plasma tHcy concentrations, irrespective of lipid or smoking status, and lowered systolic blood pressure in both normolipidemic and hyperlipidemic men, with significant diastolic blood pressure reductions in the HYL group only. Increased oral intake of cysteine may therefore be considered for primary or secondary prevention of vascular events with regard to the 2 independent risk factors of hyperhomocysteinemia and arterial hypertension.